beta(2)-adrenergic receptor (beta AR) density on peripheral blood lymphocytes has been used as an index to reflect the beta AR state of the body. Lymphocytes beta ARs are unequally distributed among lymphocyte subpopulations, with the highest density on CD8+ cells and the lowest on CD4+ cells. Thus, the measurement of peripheral blood lymphocyte beta AR density could vary with changes in CD4+ and CD8+ cell concentrations. We examined the individual and intersubject variance of beta AR density and lymphocyte subpopulations over time in 10 normal subjects, studied on 3 to 5 different d always at approximately 9:00 A.M. over a 4- to 12-wk period. Peripheral blood lymphocytes were isolated and beta(2)-adrenergic receptor density was determined by specific binding of [I-125] -(-) iodopindolol, and lymphocyte subpopulations were measured by flow cytometry. Average receptors per lymphocyte were 776 +/- 183. Whereas the absolute values of CD4+% and CD8+% cell concentrations varied little in individual subjects (coefficient of variation 9.5% and 11.1%, respectively), the individual beta AR variance was greater (coefficient of variation 22.4%). However there was a significant correlation between beta AR and CD4+% and CD8+% cell concentration (correlation coefficients: -0.58, p < 0.001; +0.51, p < 0.001, respectively). This information is relevant to interpretations of changes in peripheral beta AR in humans.